I decided to take a quick flight this morning in a 747-400 from Miami Internal to Atlanta Hartsfield. Filed a flight plan for FL320, up the East coast of Florida and then turning in towards Georgia and the airport.
I crashed and wondered why.
I was following waypoints and had auto-pilot set to hold altitude, heading and speed with auto-throttle set @ 275 knots. All was fine up to FL200, and I then got clearance from ATC to climb to FL320. I was asked to expidite the climb so increased from +1800 ft/min to +2,500 ft/min and noticed that the airspeed started to bleed off even with ATR engaged and throttles did not seem to be at full power even though the airspeed was reducing, so I reduced to +1800 ft/min again but the speed still kept slowly reducing. As I reached FL310 I got the stick shaker (170knts), went into a flat stall and was unable to recover despite knocking the autopilot off, pushing the nose down and using 25,000ft of nose down and full throttle to build airspeed and lift. The Florida Everglades now have an additional 875,000 lbs of areospace grade aluminium and wiring embedded in the swamps, along with 300 or so bodies to feed the gators.
The 747-400 can clearly cope with FL320, has the power to climb there, so why was I losing speed at that altitude with ATR on? Gear was up, flaps were up and I can't think of anything else that would cause the stall. Anyone got any ideas?
Typical, I think I just found it.
QuoteBOEING 747-400 REFERENCE INFORMATION
Maximum Range 8,400 nm
Service Ceiling 41,000 ft
BOW 397,000lbs.
Cargo 189,000lbs.
ZFW 500,000lbs.
MGTOW 870,000lbs.
MGLW 630,000lbs.
Set Fuel Load from ZFW 500,000 lbs.
Takeoff Power Reference @ MTOW 870k lbs.Dry Conditions
Average 10k ft. Runway is 109.9% N1. Max 117.2% N1.
V1 = 158 KIAS
Vr = 175 KIAS
V2 = 187 KIAS
Flaps 10-5 at 185 KIAS
Flaps 5-1 at 205 KIAS
Flaps 1-0 at 235 KIAS
Climb 1800 - 2500 fpm to 10,000 ft.
Climb 2000 fpm. to 16,000 ft. at 95% N1
Climb 1300 down to 500 ft/min from 16,000 ft. to Cruise Altitude.
Speeds: 250 ias. to 10,000 ft.
Speeds: Mach .50-.60 from 10,000 ft. to 16,000 ft.
Speeds: Mach .60-.79 from 18,000 ft. to 31,000 ft.
Speeds: Mach .80 above 31,000 ft. 91% N1
Cruise Airspeed: Mach .80 -.88 91% N1
Average burn rate 24k lbs per hour .
Approach Airspeed: 220-234 KIAS, 50% of N-1
Flaps 0-1 - 213 KIAS 11 DME
Flaps 1-5 - 194 KIAS 9 DME
Flaps 5-10 -174 KIAS 7 DME
Target Airspeed: MLW 630k lbs.
Flaps 20 - 159 KIAS
Flaps 25 - 154 KIAS
Flaps 30 - 148 KIAS
Thrust reverse to 80 KIAS
Apply brakes under 80 KIAS
Exit Runway Under 15 Knots
Clearly the climb rate was too much. I am sure I have taken the 747-400 up to those levels at 1800, but I must be mistaken.
Ah well, I'll go load the fight again and see if I can get it right this time!
I've never tried the larger Aircraft, seems rather complicated. Are there a bunch of pre-flight things you have to do before you can even take off or can you just throttle up and away you go (flaps etc. in the right position of course)?
They seem complicated but if you set the flight computer up beforehand it can be quite easy.
Create a flight plan in vroute. Load it into FSX and select your aircraft.
I usually then set:
Speed to cruise speed.
Heading to runway heading
Altitude to the takeoff cleared flight level (eg cleared for takeoff fly runway heading climb and maintain 10,000)
Do your take off, engage autopilot & auto throttle, heading and altitude.
Shift-F10 nav log to see waypoints. Adjust headings to match flight plan.
Follow ATC for FLs.
Adjust and reduce climb rate as altitude increases!
When you get near your destination airport ATC will take you off your waypoint flight plan to vector you in for the given runway.
Find the ILS frequency for that runway and enter it to Nav1 on the flight computer radio section.
As you approach the ILS tail, activate Nav1 on the radio and turn they flight computer into Nav mode.
Turn on Loc before you intersect the ILS tail and when the beacon is picked up the aircraft should turn onto the localiser.
Once lined up, turn on App which will then allow the ILS to reduce your altitude as the glide slope comes down to meet you.
On your way down turn off auto throttle and control glide slope manually.
At 500 disengage auto pilot and land manually.
Sent from my Nexus 5 using Tapatalk whilst cruising over north Florida at FL341 for FL360!